1. Field of the Invention
This invention relates to an image forming apparatus, and particularly to the image forming apparatus with a sheet carrier unit and a sheet supply tray.
2. Description of the Related Art
In conventional image forming apparatus, an image forming device in a main body forms images on a recording sheet and the sheet is conveyed from an image transferring point to a tray or a sorter by a sheet carrying mechanism.
Now referring to FIG. 1(a), a conventional image forming apparatus is described.
An image forming device 10 generally includes a sheet supply tray 6 on a main body of the image forming apparatus 1. A sorter 2 is individually placed adjacent to the image forming apparatus 1.
In this type of the image forming apparatus, a paper chute of the sorter 2 is installed such that a route of the sheet conveying in the sorter 2 becomes the same route as that of the image forming device 10. Therefore, the paper chute of the sorter 2 is located on the same position as a paper chute of the image forming apparatus 1.
Recently, the demand for a small-footprint of the whole image forming apparatus is increasing. One of the conventional techniques to meet this demand is described in FIG. 1(b) wherein a sorter 2 is arranged on an upper part of the image forming apparatus 1.
In Japanese Laid Open patent application 10-115,959, another copying device is described. The copying device is constituted of the image forming device main body, an image reader, the carrying device for feeding the paper and a relay carrying unit, where the image forming device main body is attachable to one side surface of the carrying device for feeding the paper by a fixing means such as a screw. The image forming device main body is mainly provided with a developing device, a photoreceptor, a transfer belt, a cleaning device, an electrifying roller, and optical device and a fixing device 27' and an ejecting tray 5' is provided projectingly outside the side surface on a side where the optical device 26' is provided as shown in Figure.
Further, the relay carrying unit 6' is provided with a carrying path 61' in a connected state to an ejecting part, in the carrying device for feeding the paper 4' and further, a manual paper feeding part 62' below the carrying path 61'. The carrying path 61' of the relay carrying unit 6' is provided to connect to the carrying path 28' of a paper entrance part in the image forming device main body 2', in a nearly vertical direction.
On the other hand, there is a cartridge type image forming apparatus wherein detachable devices are put on and off the main body of the image forming apparatus.
And then, in Japanese Laid Open patent 03-275,376, unity image forming devices are laminated and are covered by the outer frame body.
However, the sheet processing station of each of the above conventional image forming apparatus is not common for different types of image forming apparatuses. That is, the sheet processing station can not be exchanged with different types of the image forming apparatus.
The image forming apparatus described in Japanese Laid Open patent 10-115,959 is capable of being a common paper supply tray and a paper feeding tray. But, this apparatus has not a sorter. If the sorter is connected to the apparatus, a footprint of the whole image forming apparatus becomes large.